Breadcrumb Home > Dictionary > Index G Gaia hypothesis: Meaning and Definition of Find definitions for: Gai'a hypoth"esis Pronunciation: (gā'u), [key] a model of the earth as a self-regulating organism, advanced as an alternative to a mechanistic model. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. GAI gaiety ✖ Related Content Daily Word Quiz: donnybrook Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language